And I want to state your thinking isn't totally off. Big premium pairs play better in HU pots, so you do want to bet enough to limit the field. You don't want AA in a 5 way pot. However, the 4xbb + 1bb etc is a good way to limit the field without over committing your stack, and still getting value from other hands such as AQ, AJ, KQ, small pocket pairs, suited connectors etc. You make them pay a good bit to play, and your fine with it because you know you are ahead going into the flop.

But your thinking of betting enough to get the job done is correct. If the table is incredibly aggressive and you see alot of people are calling raises 4xbb to see the flop, but 5xbb or so is limiting the field then go with the 5xbb. It just doesn't need to be excessive and you don't want to raise because you want "idiots" or "bad hands" out of the pot. You want them to come along, just not too many of them.

And do you understand what I was saying about the KK on the Axx board?? If not I can try to dig up a link or two for you to explain.